1. Field of the Invention
The present invention relates to an optical pickup apparatus having a skew adjusting mechanism for adjusting a skew of an optical pickup with respect to an information recording face of a recording medium, wherein the optical pickup reads out information recorded on the information recording face and is capable of moving in parallel with the information recording face in the radial direction.
2. Description of the Related Art
As shown in FIG. 10, in a conventional optical pickup moving mechanism 100, a feed screw 101 and a pair of guide shafts 102 are respectively arranged in parallel with each other, and an optical pickup 103 is movably arranged in the feed screw 101 and the guide shafts 102.
At an end portion of the feed screw 101, there is provided a drive motor 104. The feed screw 101 is rotated in the normal and the reverse direction by a drive force generated by the drive motor 104.
When the feed screw 101 is rotated, the optical pickup 103 is moved along the pair of guide shafts 102.
As shown in FIG. 11, the feed screw 101 (shown in FIG. 10) and the pair of guide shafts 102 are arranged being opposed to an information recording face of the recording medium 107 which is arranged at a predetermined position by a turn table 106 and a damper 108 attached to a rotary shaft 105a of a spindle motor 105. The feed screw 111 and the pair of guide shafts 102 extend in the radial direction of the information recording face.
The optical pickup 103 is moved along in the radial direction of the information recording face of the recording medium 107 by a drive force generated by the drive motor 104 shown in FIG. 10.
The optical pickup 103 includes a light emitting element (laser diode) and a light receiving section (which are not shown in the drawing). The optical pickup 103 also includes and an objective lens 103a arranged being opposed to the information recording face of the recording medium 107. A laser beam emitted from the light emitting element is condensed by the objective lens 103a (shown in FIG. 12) and irradiated onto the information recording face.
When reflected light (returning light) reflected on the information recording face is received via the objective lens 103a by the light receiving section, information recorded on the information recording face can be read out.
That is, the optical pickup 103, which is positioned by the optical pickup moving mechanism 100 so as to face a predetermined position on the information recording face, reads out information recorded on the information recording face by a laser beam irradiated onto the information recording face via the objective lens 103a. 
In order to accurately read out information recorded on the information recording face by the laser beam, it is necessary to adjust an angle α formed between an optical axis L of the objective lens 103a and the information recording face as shown in FIG. 12.
In order to make the light receiving section of the optical pickup 103 accurately receive a beam of reflected light, which has been reflected on the information recording face, it is necessary for the beam of reflected light to be guided into the light receiving section without decreasing a quantity of light reflected on the information recording face. Therefore, it is required that a skew of the optical pickup 103 (of the objective lens 103a) with respect to the information recording face is adjusted.
Especially, in the case of an optical recording medium of high-density type such as DVD (Digital Versatile Disc), recording pits are formed on the disc in a highly dense state. Therefore, the skew of the optical pickup 103 needs to be adjusted accurately.
In the above conventional optical pickup moving mechanism 100, a skew adjustment of the optical pickup. 103 is made by moving and adjusting a pair of guide shafts 102 shown in FIG. 10.
In the case of adjusting the skew of the optical pickup 103 in the radial direction (direction indicated by arrow A in FIG. 10) of the optical axis L of the objective lens 103a, the guide shafts 102 are simultaneously moved so as to be adjusted. In the case of adjusting the skew of the optical pickup 103 in the tangential direction (direction indicated by arrow B in FIG. 10) of the optical axis L of the objective lens 103a, the guide shafts 102 are respectively and independently moved so as to be adjusted.
However, in the skew adjustment of the conventional optical pickup 103, only the pair of guide shafts 102 are moved and adjusted, and the feed screw 101 is fixed to a fixing member such as a chassis so that the feed screw 101 cannot be moved.
Therefore, after the skew of the optical pickup 103 has been adjusted (after the pair of guide shafts 102 have been moved and adjusted), a minute misalignment is caused in the parallelism between the feed screw 101 and the pair of guide shafts 102. When the optical pickup 103 is moved in the radial direction of the information recording face, there is a possibility that an excessive load is given to the feed screw 101 and the drive motor 104.